<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    <style>
      .basic {
        width: 400px;
        height: 100px;
        border: 1px solid black;
      }
      .normal {
        color: peru;
      }
      .sad {
        background-color: green;
      }
      .happy {
        background-color: hotpink;
      }
    </style>
  </head>
  <body>
    
    <div id="root">
      <div class="basic" :class="mood" @click="changeMood">{{name}}</div>
    </div>

    <script>
      new Vue({
        el: "#root",
        data: {
          name: "尚硅谷",
          mood: "normal",
        },
        methods: {
          changeMood() {
            this.mood = "happy";
          },
        },
      });
    </script>
  </body>
</html>
